Writing instrument cap



FIG. 1 is a perspective view of a writing instrument cap according to the present invention;

FIG. 2 is a front elevational view thereof;

FIG. 3 is a rear elevational view thereof;

FIG. 4 is a right side elevational view thereof;

FIG. 5 is a left side elevational view thereof;

FIG. 6 is a top end view thereof; and,

FIG. 7 is a bottom end view thereof.

The broken line showing the inside in FIG. 7 is environmental matter and forms no part of the claimed design. 

What is claimed is the ornamental design for a writing instrument cap, as shown and described. 